The present invention relates to a device for supporting and rotating a hanging plant and more particularly to such a device to rotate the hanging plant on a uniform growth promoting schedule as a function of the presence of adequate growth promoting light.
It is well recognized that a plant will grow in the direction of sunlight and may eventually become lopsided if the plant is not rotated on a consistent basis. This is especially true in situations where the plant is hung adjacent to a window and only receives sunlight in one direction. Several attempts have been made to promote uniform plant growth as disclosed in the following patents:
U.S. Pat. No. 4,216,619 discloses a device for rotating a plant as moisture evaporates from the container holding the plant. Rotational motion on the plant is accomplished through the use of a spring that is linearly distorted by the weight of gravity. A spiral motion conversion mechanism connected to the spring converts the linear distortion into rotational motion;
U.S. Pat. No. 4,446,653 discloses a device for supporting and rotating a hanging plant which is responsive to the addition and evaporation of water in the plant holder. The device consists primarily of a cord attached to a fixed hook at one end, and a plant at the other end. The cord extends in length and winds in one direction in response to an increase in the weight of the plant due to the addition of water. Conversely, the cord retracts and winds in the opposite direction in response to a decrease in the weight of the plant due to the evaporation of the water;
U.S. Pat. No. 5,315,784 discloses a device for rotating a hanging plant. Counteracting coaxial tension springs rotate the plant in one direction when the plant is watered and then back in the other direction as the water evaporated from the plant. In each case, the same principles of operation are employed; that is, the use of gravitational force on the plant, responsive to increases and decreases of the weight of the plant. These devices generally consist of springs or cords which, when extended or retracted, impart a rotational motion on the plant itself. It should be noted, however, that the amount of rotational motion on the plant ultimately depends on the amount of water present in the plant; and
U.S. Pat. No. 5,546,698 discloses a system to obviate the dependence on the amount of water present in the plant by automatically rotating a hanging plant at predetermined intervals. This system includes an apparatus for supporting and rotating a hanging plant with a housing having an upper hook fixedly attached to a top surface thereon and a lower hook that extends from a bottom surface of the housing for hanging and supporting a plant. There is a light sensing mechanism, disposed on the outside of the housing for detecting the amount of ambient light incident upon the housing along with a rotary mechanism, disposed within the housing, for periodically rotating the lower hook relative to the upper hook whenever the amount of ambient light detected by the light sensing mechanism exceeds a threshold value. The rotary mechanism further includes a DC motor within the housing, a reduction gearing assembly connected to an output shaft of the motor, and a vertically disposed shaft, rotatingly coupled to the reduction gear assembly and connected to the lower hook. In addition, a first timing mechanism responsive to the light sensing mechanism determines when the DC motor is to be energized, while a second timing mechanism, also responsive to the light sensing mechanism. controls the duration of time that the DC motor is energized. This meritorious improvement on prior plant rotating devices still possessed a few drawbacks. The power supply, such as a single battery, functioned both to drive the motor and as a current source for the light sensor and other electronics some of which was continuously energized. This resulted in an undesirably short battery life. Moreover, plant rotation was limited to a single rotational sense. A need, therefore, remains for a device that will support an ordinary houseplant while automatically rotating it at pre-selected intervals in order to promote even growth of the plant.
Plants tend to grow toward the sun due, at least in part, to the phenomenon that the portion of the plant stem facing the light source experiences a greater growth rate than does the stem portion which faces away from the light source. A plant rotating device such as the aforementioned U.S. Pat. No. 5,546,698 patent continually rotates in one sense and the plant follows the light often forming a corkscrew or helical pattern. Such a growth pattern is interesting, but generally undesirable. Depending on the type of plant, the helix may descend from the plant pot or may grow upward eventually wrapping itself about the support. Unfortunately, the continual rotation requires constant energy resulting in a corresponding battery drain such that in order to function in a desired manner a battery may need to be changed on a regular basis and for most plants it is desirable to avoid the helical growth pattern sometimes found with apparatus of the prior art.